Thermally driven air conditioning units that use liquid desiccants as a working fluid are used in a variety of heating, ventilation and air conditioning (HVAC) applications. Typically, the type of desiccant used by liquid desiccant air conditioners (LDACs) has a profound effect on the design of such units. Glycols and solutions of halide salts are used as liquid desiccants in some industrial equipment. For example, halide salts such as lithium chloride and lithium bromide are currently used as desiccants in certain HVAC applications. However, such salts are relatively expensive and their solutions are corrosive to most ferrous and nonferrous metals. Moreover, glycol is volatile and needs regular replacements thereby making it expensive as well as harmful to the environment.
In certain HVAC systems, activated alumina is used as the desiccant. However, activated alumina is heated to a temperature of about 2000° C. for regeneration. Certain other systems use polymer-based desiccants such as poly-vinyl alcohol foam and calcium chloride. Such desiccants require heating for regeneration of the material and even small quantities of carbon dioxide in the atmosphere can render the material inactive over a period of time.